The present invention relates to harrows, and more specifically to spike-tooth harrows with means for adjusting the operating angle of the teeth.
Spike-tooth harrows are used extensively in agriculture for such operations as leveling the soil and breaking up large clods. Ranks of teeth are supported at a preselected working angle, which is either fixed or adjustable. One of the most common types of adjustable angle harrows includes pivoting tooth bars connected to linkage structure, which often takes the form of a four-bar linkage arrangement, and movable with a lever. Although these and other types of adjustable harrows have in general worked satisfactorily, the linkage arrangements for adjusting and maintaining the working angle have, for the most part, significantly increased the cost, complexity and size of the harrow over that of the nonadjustable types. In some harrows, rigid fore-and-aft extending, connecting and adjusting structure tends to limit harrow flexibility.